Flattening of affect, a constriction in the range of content-appropriate expression of feelings, is the most common clinically observed disturbance of affect. In schizophrenia, flat affect is a powerful predictor of treatment outcome. Similar behaviors are typical in progressive Parkinson's Disease and may be found with right hemisphere pathology. One major purpose of the proposed work is to develop a measurement system for the study of affective disturbances in psychiatric and neurologically-impaired populations, and in so doing to eventually produce a well-standardized battery for clinical purposes. A second major purpose is to examine, in these patient groups, the characteristics of several parameters of affective processing, including channel (voice, face), processing mode (perception, expression), and valence (positive, negative). By systematically examining the relationships among these variables, it may be possible to reduce the number of variables and to develop a more efficient and streamlined set of measures. A final aspect of this work will be a set of comparisons designed to illuminate possible brain mechanisms underlying flat affect in schizophrenia. Since affective disturbances in the Parkinson's patients reflect mainly subcortical involvement whereas the affect in right hemisphere stroke patients reflects mainly cortical pathology, comparisons will be made between the psychiatric and neurological groups using our measures of affective processing. We will also make such comparisons with patients on and off neuroleptic drugs, since such drugs are known to produce a type of flat affect. To further examine underlying mechanisms, we will test schizophrenic patients with procedures that provide indices of hemispheric specialization for affect, such as ratings of facial asymmetry. To address the first two aims, patients will be videotaped while deliberately producing affective facial expressions and audiotaped during vocal expressions, which will be assessed for appropriateness and intensity. Patients will also be tested on perceptual tasks using affectively-toned faces and voices. To address the third aim, flat and non-flat schizophrenics will be examined on lateralized tests of affects.